Line segments and corners of distractors are equally important in causing interference.

In this series of studies we examine the importance of component features (line segments and corners) of a distractor in producing distractor interference. We postulated that corners are nonaccidental features and therefore crucial components in the processing of distractors (Kritikos and Pavlis 2007, Experimental Brain Research 183 159-170). We presented non-degraded or degraded (line segments or corners removed) distractors (line drawings of tools or musical instruments) simultaneously with a target, either at fixation or peripherally. Non-degraded as well as degraded distractors caused higher levels of interference (increased reaction times and a greater number of errors), particularly when presented at fixation, while non-degraded distractors caused greater interference than degraded. Contrary to expectation, however, there was no difference in the level of interference caused by lines-missing and corners-missing distractors, either at fixation or at periphery. Thus, we conclude that, where response to a complex object is required, both lines and corners are equally important components in the visual processing of distractor stimuli.